In my opinion, this is a pullet. Most importantly, at nine weeks that is really small and pale comb to be a cockerel. I also could be wrong but in my experience, I agree with The Moonshiner about rust leakage. For your bird, I don’t think that is “rust leakage” on the shoulders since the orange coloring is pretty consistent throughout all the feathers. Rust leakage as I’ve seen it on my BYM cockerels is smaller kind of random patches of dark red (rust color) and usually doesn’t contribute to their overall coloring. It might match their hackles and saddle feather colors but wouldn’t be consistent throughout all the feathering. I attached some photos of rust leakage of my BYM cockerels (around 2-3 months old in these pics). Basically you can see that they have rust patches on the wings that might be consistent with their hackles and saddle feathers, but not necessarily with their overall coloring.
Like I said, I could be wrong but I’ve had a lot of BYMs of various mixes. I always used comb size and comb color almost exclusively to identify cockerels. That was always the key indicator for me and became apparent after 8 weeks. The rust leakage came later usually in tandem with hackles and saddles and always seemed to be patchy like the pics below.